This might bring halt in the proper supply of the oxygen and blood to the baby. Exercises that are safe during pregnancy are pelvic tilt, Pilates etc. Exercises are safe if the pregnancy is normal or healthy. Those pregnant women with complications are required to avoid any hard or even moderate exercises. Bleeding is one of the complication in which exercise is advised to be avoided. If light bleeding is being observed then after it stops exercise can be done. The reason is that it is quite normal in the first half of the pregnancy.